Ledley King's World Cup appears to be over after the England defender damaged his groin during Saturday's draw with the USA, an injury the coaching staff fear will make him unavailable for the next three weeks.

The medical team will continue to assess King. Fabio Capello confirmed the centre-half injured an abductor muscle in the opening moments of the 1-1 stalemate at the Royal Bafokeng Stadium. King complained of tightness immediately after Steven Gerrard had opened the scoring and, though he played on through the first half, he was withdrawn at the interval.

While the problem is not related to King's chronic knee complaint, the medical record always suggested Capello's initial assessment, that the 28-year-old would be absent only for Friday's game against Algeria in Cape Town, would prove optimistic. Niggles sustained by the Tottenham defender, who is unable to train properly because of his knee problems, tend to rule him out for three weeks at the very least with the management staff privately accepting as much last night.

Capello will seek another medical bulletin today though the risk in selecting King in the first place after a three-year absence at this level appears to have been exposed. Having lost Rio Ferdinand to a freak knee injury on the eve of the tournament, the Italian is now left with Jamie Carragher, Matthew Upson and Michael Dawson as his options to partner John Terry at the heart of his defence. "We have those three defenders," said Capello. "I hope we will not have any more injuries."

There is uncertainty across England's back line at present – they have kept only seven clean sheets in Capello's 25 games in charge, and only one in their last 10 matches – and the manager will scrutinise Robert Green's reaction to his horrendous handling error against the USA in training over the next few days before determining whether or not to select the goalkeeper against Algeria.

Although no decision has been taken as yet, Capello would have no qualms about dropping the 30-year-old should he and the squad's sports psychologist, Christian Lattanzio, determine Green is still showing the strain of the mistake which presented Clint Dempsey with a soft first-half equaliser on Saturday.

Just as significantly he will gauge the effect that error has had on his relationship with his defenders and assess whether faith in their team-mate has been eroded beyond repair. "We have to wait," said the Italian. "We will think about this problem and will look at him to see how he does, psychologically. Goalkeepers make mistakes. You have to accept that. He played well in the second half but a mistake is a mistake. We will speak to him and then decide."

Capello's alternatives in goal are the rookie Joe Hart, who has impressed in training but is deemed too inexperienced, and the veteran David James who remains perplexed as to his inability to force his way into the team's line-up. The 39-year-old claims he is fully fit and available but appears to have been overlooked for footballing reasons.

Asked to assess his fitness, James replied: "Super. I am fit and well. I'm right. I was, like Joe [Hart], 'up for selection'. There wasn't an issue. I went to the gym earlier in the week rather than going out to training and suddenly everyone was saying I had a problem with my knee. That wasn't the case."

Discarding Green now as the team's first choice could have a profound effect on the West Ham goalkeeper's confidence, as well as his future career at this level, yet Capello's decision will be made purely for the benefit of the team. The player himself issued a public apology for allowing Dempsey's skimmed attempt from distance to dribble over the line.

"The manager would have to answer whether he is going to stick with me or not," said Green. "I'll be prepared whether I'm in or out, and ready to play, wanting to play. I walked in at half-time, said sorry to the chaps and I apologise to however many million people at home as well. I am willing to work mentally on it. I've done it before, I'm 30 years old and I've learned to deal with these things."

Lattanzio, hired initially by Capello to help exorcise what the manager deemed to be "a big problem in the mind" following England's failure to qualify for Euro 2008, will be available to help him through the days ahead. "I'm desperately keen to play," added Green. "This is the biggest stage in the world and I'll be twice as determined now for this not to happen again. You want to prove people wrong and be a man about it. It's how you bounce back that counts."